Researchers may have natural solution to unnatural grass

ERIC BERGER, HOUSTON CHRONICLE |
October 26, 2009

When ecologist Mark Simmons stands on a well-kept lawn, he can appreciate its beauty and the tingle of close-cropped grass under bare feet.

He also can't help but see water, fertilizer, pesticides and lawn mowers.

“If you think about most lawns, they're basically a single species on life support,” he said.

For most homeowners the greenest-looking component of their residence — lawns of St. Augustine and Bermuda grass — belie their steep environmental costs of consuming half the area's drinking water and filling bayous and bays with pollutants.

So Simmons, who works at the Lady Bird Johnson Wildflower Center of The University of Texas at Austin, has been searching — with some success — for blends of native grasses that make for attractive, drought-resistant lawns with less of an ecological footprint.

“We're interested in solving an environmental problem with native plants,” he said.

The idea seems especially salient after a summer during which one-fifth of Texas was mired in an “exceptional” drought, the worst category tracked by the U.S Drought Monitor.

Using a two-year grant from Wal-Mart, Simmons and others at the wildflower center have developed a blend of seven species of native, thin-bladed grasses. They tested this native grass against buffalo and Bermuda grass species and a combination of the two.

Simmons said the early results are promising: The blend of natural grasses established itself much better than Bermuda grass, more effectively suppressed weeds, had a higher density and required less mowing because it grew more slowly. It also proved to be more drought-tolerant.

Making seed available

The wildflower center is now working with seed growers to make the mix more widely available, Simmons said.

The research comes after recent work by scientists to better quantify the environmental impact of lawns.

Using satellite mapping, NASA research scientist Cristina Milesi found that some 40 million acres of the U.S. and up to 5 percent of urban areas, are covered by lawns, making turf the country's largest irrigated crop. Keeping a green lawn in many areas, even including “wet” regions like Southeast Texas, requires significant resources.

Lawn watering accounts for about 54 percent of residential water usage in Texas, said Jim Blackburn, an environmental lawyer and adjunct professor in law and the environment at Rice University. That's water that otherwise would be flowing into coastal bays and increasing their vitality, he said.

Consider this, he said: We plant grass plugs. We water them. We fertilize them. Then when we achieve success, we cut the grass. This opens it to increased evaporation, so we have to water it more. It makes the grass vulnerable to insects, herbivores and competition from weeds.

Process repeats itself

So we fertilize it, he said, and start the process all over again.

Further, a recent study by California environmental horticulturists found that current estimates of pollution from fertilizers and pesticides used on lawns may underestimate the amount washed into storm drains by 50 percent.

An advocacy organization for the lawn care industry, Project EverGreen, has a different view.

“As a consumer you can stand on a piece of concrete in the middle of summer versus a patch of well-kept grass and feel quite a difference,” said Den Gardner, the group's executive director. Lawns can be up to 30 degrees cooler than asphalt, he said.

A cooler Houston is obviously a good thing, as is a city that preserves some areas for water retention during its regular flooding. A healthy lawn absorbs rainfall up to six times more effectively than a wheat field, and four times better than a hay field, Gardner said.

All of which means lawns aren't inherently evil, Simmons said.

“Lawns have been demonized in some parts of the country,” he said. “I've got kids, I like playing outside on the lawn. We're not telling people to rip up their lawns. What we are saying is there's a natural solution to the problem of struggling to keep your imported lawn alive.”